Both lightguides and computer networks are readily available and their uses are continuously growing. It is anticipated that computer networks will benefit by using lightguides as the transmission medium because they provide ground loop isolation, minimize electromagnetic interference, save space, and provide future cost savings over coaxial cable systems where equalization is required.
While conventional computer networks today do not use lightguides, their use in future facilities is currently under study. (See the article by E. G. Rawson et al. entitled "Fibernet: A Fiber Optic Computer Network Experiment", published in the Fourth European Conference on Optical Communications Conference Proceedings Genoa, Italy, September 1978 Conference Proceedings. However, the use of fiber links involves more than simply replacing the coaxial cable with a length of optical fiber. The optical signal must be detected and converted to an electrical signal and, conversely, the electrical signal must be converted to an optical signal. Inasmuch as these processes are separate, the use of two optical links is required. Furthermore, in a system employing a contention protocol, this must be done in a manner which permits each station to monitor all other stations while transmitting so as to detect the presence of other interfering signals. Simultaneously, the interface network must be capable of avoiding reflections of the incident signals.